1. Field of the Invention
The present invention relates generally to a method of an iron Fe ion implantation into a semiconductor substrate and is directed more particularly to a novel method of Fe ion implantation into a semiconductor substrae of an N-type conductivity with which the lifetime of minority carriers can be controlled effectively.
2. Description of the Prior Art
If the temperature dependency of the lifetime of minority carriers in a semiconductor, for example those manufactured out of silicon crystals can be reduced, when the semiconductor may be advantageously used as various semiconductor devices, especially transistors, diodes, thyristors, etc., which may be used with large amounts of electric power.
The art, for example, U.S. Pat. No. 3,953,243 shows the control for the lifetime by utilizing gold, (Au). Recently, platinum, (Pt), has been used for the same purpose. Au and Pt have great temperature dependency characteristics when used as a lifetime reducer. When they are doped into a semiconductor substrate of an N- or P-type conductivity, they become an acceptor or donor, increasing the resistivity of the semiconductor substrate thereby and hence reducing the current capacity of a semiconductor device.